Present day electronic systems, such as those employed for data processing, utilize a packaging arrangement having a single backplane (mother board) and a plurality of logic boards, sometimes referred to as daughter boards. The surface of the backplane includes a plurality of connectors into which respective logic boards are plugged in orthogonal relation to said surface. As such electronic systems become more complex, the task of routing electrical signals and of increasing the speed of system operation becomes more arduous. To accomplish these goals, a dual backplane configuration is advantageous. Thus, a pair of parallel, spaced-apart backplanes are provided with a plurality of parallel, spaced-apart logic boards oriented at right angles to the backplanes and disposed therebetween to form a card rack. However, it is apparent that such a configuration poses a unique interconnection problem. In order to make electrical connections between the opposite extremities of each logic board and the respective backplanes, it is necessary that means be provided to permit the logic board to slide into position between the backplanes. Once the logic board is in place, the connector system must be actuated to make the electrical connections.
Connector systems have been developed in the industry for use with dual backplanes. One such system is described by Fujitsu Limited of Kawasaki, Japan in a technical paper entitled "High Density Three Dimensional Stack Packaging for High Speed Computer", published in the Proceedings of the 1982 32nd Electronics Components Conference" relative to the "Components, Hybrids and Manufacturing Technology Society" program. As seen particularly in FIG. 9, page 452 of the Proceedings, the Fujitsu system is based upon the surface mounting of pin contacts on both the backplanes and at opposite extremities of the logic boards. Electrical connections are made via movable, double position, female connectors. Initially, the movable connectors are installed such that they engage only the pins emanating from male connectors disposed on the interior facing surfaces of the respective backplanes. In the installed position, the movable female connectors are slid into contact with the male backplane connectors. The logic boards with pins emanating from male connectors mounted on opposite extremities thereof are positioned relative to the homologously disposed pins on the respective backplanes. The female connectors are then moved toward the logic board pins which enter the connectors, such that the contacts of the female connector bridge both male connectors.
The system described by Fujitsu uses connectors which have a very small pin pitch and this has resulted in significant alignment and registration problems. Additionally, the sliding connectors mounted on the respective interior surfaces of the dual backplanes require considerably more space in this area than conventional connectors and the signal paths via the connector pins are considerably longer than optimum. The latter is an important consideration in high speed system operation. Finally, the cam mechanism taught by Fujitsu in the reference paper is located inside the card rack thereby limiting access to the mechanism for maintenance and repairs.
What is described is a dual backplane configuration system, which eliminates the foregoing deficiencies of the Fujitsu system, is economical, and relatively simple to implement. The pin-through-backplane connector system of the present invention fills such a need.